Observations and ideas on FPS .WAD design
By David J. Finnamore
doom@elvenminstrel.com

Stairs automatically occupy the player's mind to a certain extent. In the physical world, stairs require more coordination than level floors, so our subconscious minds automatically designate more attention to our legs and feet when we walk up and down them. Even though no more attention is actually needed by the player to manage the virtual stairs in a FPS game, his mind subconsciously thinks of itself as "busy" doing something. This can help prevent him from being as ready for an ambush assault.

A texture can be made to blink (or given any other lighting effect) without affecting the sector it appears to border. This is useful for making effects such as the blinking lights on warning signs or traffic barriers. Here's how:

Make a pair of dummy sectors outside the play area, one inside the other. Set the outer dummy sector to the brighter light level, the inner dummy sector the darker light level; give the outer dummy sector a special lighting property such as blink. Make a two-sided line def in the play area that faces both sides of the outer dummy sector, and give it a middle texture on the visible side. The texture will blink but the sector it appears to touch will not. Of course, if no special lighting property is assigned to the outer dummy sector, the trick texture will simply have a different lighting level than the surrounding textures, which can also be useful for fires or other special effects. Two words of caution: 1) THINGS in the immediate vicinity of such a trick texture will also be bestowed with the lighting effect or light level of the outer dummy sector. That looks rather odd; so build the area in such a way as to prevent monsters and players from getting into the affected area. 2) As with all tricks that use middle textures on two-sided line defs, remember that only single-patch textures are suitable; multi-patch textures will cause HOM.

Force a player to knowingly run into a room with, or otherwise toward, (a) large monster(s) in order to continue on a level.

Place monsters on moving floors that carry them in and out of sight of the player in a shooting gallery situation.

Use "key" textures decoratively in places other than door jams.

Lock players in a room with monsters.

Use lighting contrasts to show players where their doom lies next.

Use dropping pillars (moving floors) or similar devices to place monsters unexpectedly in places the player is returning to.

Use a single switch to lower more than one lift. E.g., a room may have several columns, some of which are actually lifts; when a player (who has navigated the room previously) finds himself in a small room with a single switch, he presses it to lower that column into the room of columns, and simultaneously lowers others which may contain monsters &/or goodies.

Use trip lines in front of turbo doors/lifts to open them suddenly just as the player reaches them, with monster attacking full in the face.
· As player travels down a flight of stairs, which end in a 90-degree turn, he trips a line that opens a turbo door right in his face on the wall at the bottom of the stairs, forcing him into an ambush.
· Do the same as above but several doors all around open, some in sight, some out of sight, so that he has nowhere to run if he is so inclined, and has more monsters to face soon in any event.

Use trip lines to open monster closets behind a player - the sound of it opening is the real beauty of it.

When player goes to grab something he desperately needs, he trips an invisible tag line that opens a monster-occupied, possibly fenced-in area right behind him, or around the corner he just came from and must return to.

Have monsters "come out of the woodwork" with one-way walls in spots around a room.

A lift can serve as both a shelf and a step, or as a blockade and a step, or as a windowsill and a step, etc.

Use initial placement of a deaf-guard to indicate an otherwise unnoticeable hidden door/passage.

Cage the big guys so that what seems too dangerous is survivable if you run instead of standing your ground - they can't follow you.

Switch lowers floor rather than raising lift - exposing multiple chambers/hallways with monsters/goodies. Especially effective if the player sees something valuable and expects to get it by pressing the switch - of course, you do reward him with it shortly afterward if he earns it.

Instead of, or in addition to, keys, use unnavigable territory (slime/steeps) that will become navigable via moving floors or whatever after the player has completed sufficient parts of the level.

Provide a "backdoor" into a difficult-level room full of monsters so that a thorough, lucky, or repeat player can defeat them with a feeling of strategy. That provides incentive for at least one repeat play, and rewards a careful, strategic approach.

Keep the player from any knowledge of the extent of the level - just keep letting him discover more and more of it. Even make it look at first like he's seeing all or most of it, then open up a little door to a whole new set of rooms and corridors. Bring him back to the start to finish.

Place the player on a bridge with acid on both sides, being shot at by at least 2 or 3 monsters from each side, fairly close range. It's impossible to stay on the bridge because the shots knock you off. Make a way for the player to duck back or up or down (only a little) so he can take the monsters on one direction at a time if he's smart. Or make something he can use as a block for one direction at a time. Delivery to the bridge via a short downward lift works well; the lift will keep popping him back out of the line of fire unless he catches his head in the wall.

Force the player to run toward something in order to get what he needs (before a remote door closes, or a lift returns, etc.) and let him run full force into a trap.

Keep a tall monster, like a baron, at shooting gallery distance by providing an escape tall enough for player but not for monster.

Give the player the map power up early on in a complex level such that his knowledge of the map will increase the suspense.